The invention relates to a process and a device for the automatic and rapid recognition of faults in the surface or the dimensions of an object, and also for recognizing the position of the object in the field of view or field of operation of a measuring or operating device, employing a focusing optics and a row of photo-diodes.
For the automatic recognition of faults in an object, it is known to focus the area of the object which is to be investigated onto a projector provided with a scale employing an anamorphotic lens system. In this way a comparatively small fault occurring only in one coordinate direction can be clearly recognized and measured. The linear dimensions of an object are determined, as is known, using so-called rows of photodiodes. The section of the object which is to be measured is focused onto the diode row employing a lens system; if, on the other hand, the surface of an object arranged, for example, in the field of view of a measuring device is to be investigated or measured, a photodiode matrix is employed. The individual diodes of the matrix can be operated by means of a shift register. They are consecutively connected to a data signal integrator with the frequency of a pulse generator. Thus it is possible to determine the dimensions of the object taking into account the focusing factor. Furthermore, by means of an actual-theoretical value comparison of the measured voltage signals with stored values, it is possible to recognize structure faults or a fault relative to the position of the object within the field of view of a measuring device or in the operating field of an operating device. A measuring device of this type which operates by means of a photodiode matrix or a photodiode row is known per se. The expense required to drive and analyze the quantity of data supplied by a photodiode matrix is comparatively high-in comparison to a photodiode row which contains a considerably smaller number of photodiodes. This constitutes a disadvantage if, for example, the objects in question (small work pieces) are to be investigated. Often, for example, it is only necessary to determine whether the object lying in the field of view is damaged and must thus be eliminated from a series. The question as to where the damage is situated and the nature of the damage is here of subordinate importance. In processing machines it must frequently be insured that the object is arranged correctly in the feeder to the operating station or is positioned within the operating field of the machine. With high-speed machines, the times available are short since a recognized fault necessitates further treatment.